This invention relates to apparatus for mounting and removing a hub from a shaft. More specifically, the invention concerns utilization of a double-acting, hydraulic cylinder in an arrangement that may be used to both force a hub on a shaft and to remove a hub from a shaft.
In the rotary machine art it is common practice to move a hub of a coupling, impeller, disc and the like onto a shaft over which the hub has been preliminarily applied or to displace a hub from such a mounted position. Numerous types of apparatus have been used to accomplish this function.
The prior art includes devices wherein hydraulic fluid is supplied to expand a chamber to force a hub onto a shaft. Some means for securing the device relative to the shaft such that the expansion force may be used to force the hub onto the shaft is commonly provided. However, the use of the same apparatus to remove the hub from the shaft required additional structure for securing expansion apparatus to the hub. As can be seen in U.S. Pat. No. 3,772,759, additional structure may include longitudinally-extending rods which are secured internally within the hub. These rods are connected to a separate structure against which the expansion portion must be mounted.
Another type of device which is the subject matter of an earlier-filed, commonly assigned U.S. patent application, utilizes a cylinder and a piston which can be mounted in a first position with the cylinder secured to the shaft such that upon the application of a pressurized fluid, the piston is displaced forcing the hub on the shaft. However, to effect removal of the hub from the shaft, the assembly is reversed and placed in the opposite direction with the cylinder abutting the shaft and with an exterior surface of the piston threadably engaging an interior surface of the hub. Pressurized fluid may then be supplied to the cavity to effect displacement of the hub to remove it from the shaft.
The herein device is simpler and accomplishes multiple functions in a different manner. The herein device uses a cylindrical body portion to engage the threaded end of the shaft. The cylinder defines a portion of the cavity and a piston is mounted about the cylinder defining together with the cylinder a pair of cavities. These cavities are connected to a hydraulic system such that pressurized fluid may be supplied to the first cavity to force the piston in one direction for assembly and the second cavity to force the piston in an opposite direction for disassembly. In this manner a double-acting hydraulic cylinder is use for assembly and disassembly of hubs on a shaft. The use of a four-way valve together with a pressurized source of fluid may be utilized to control the direction of flow of the pressurized fluid.
Additionally in the herein device, a portion of the piston includes a piston flange which may either directly engage the coupling to force it into position, or may include a threaded opening into which a bolt may be secured such that upon pressurized fluid being supplied to the first cavity, the bolt engages the coupling forcing the coupling to its mounting position. To remove the coupling, a separate opening in the piston flange such as a clearance opening is utilized through which the bolt is inserted into a tapped opening in the coupling. The threaded opening could also be utilized to secure a bolt extending into a tapped opening of appropriate alignment.